Electric condenser



June 29, 1948. D. A. CLOUET ELECTRIC CONDENSER 2 Sheets-Sheet 1 Filed May 1, 1945 June 29, 1948. D. A. CLOUET ELECTRIC CONDENSER 2 Sheets-Sheet 2 Filed May 1, 1943 INVENTOR D/D/[E/QCZOUET Patented June 29, 1948 ELECTRIC CONDENSER Didier A. Ciouet, Boulogne-Billancourt. France, assignor to International Standard Electric Corporation, New York, N. Y., a corporation of Delaware Application May 1, 1943, Serial No. 485,403 In France February 13, 1942 Section 1, Public Law .690, August 8, 1946 Patent expires February 13, 1962 a 4 Claims.

The present invention relates to variable con- I densers, and more particularly to variable condensers in which the capacity is varied by lateral displacement of parallel plates.

An important object of the invention is to provide a variable condenser in which the capacity change will be negligible at the beginning of displacement of the plates thereof.

Another object is to provide a condenser which will pass a relatively broad band of frequencies.

An additional object of the invention is to provide a condenser which will render it possible to obtain a. serviceable spread of low frequencies.

A still further object is to provide a condenser adapted for use in connection with generators of beat frequencies requiring a relatively wide spread of frequencies.

Another object is to provide a variable condenser in which variations in capacity are achieved by moving certain of the plates thereof longitudinally on an axis common to said plates.

Another object of the invention is to provide a variable condenser in which certain of the plates thereof are adapted to be moved laterally with respect to certain other plates thereof, on an axis common to all of said plates, either in response to rotary or lateral force.

A still further object is to provide a support for a variable condenser in which certain of the plates thereof are movable laterally, which will assure complete alignment of all the plates thereof under all conditions of operation.

An additional object is to provide a variable condenser in which capacity changes are effected by lateral displacement of the plates thereof and in which such displacement is indicated on a calibrated dial.

Another object of the invention is to provide a variable condenser in which the movable parts will be subject to negligible degree of wear.

A still further object is to provide a power coupling means in a variable condenser which will operate with a. minimum of friction.

According to a characteristic feature of the present invention, a plurality of plates are disposed in parallel relationship on a common axis. One or more of these plates are arranged in spaced and intermediate position relative to others of said plates. They are electrically connected and mounted on a shaft to be moved laterally with respect to the other plates. The latter plates are provided with central openings permittlng passage therethrough of the shaft.

The shaft referred to is adapted to be moved longitudinally either in response to lateral or rotary actuating means. Lateral actuating means may include an additional shaft axially disposed with respect to the first named shaft, and engaging the latter in a contact with a relatively small portion of its end surface. This engagement prevents the transfer to the first named shaft of any variation in alignment that may be imparted to the actuating shaft during operation. A spring is provided at the other end of said first named shaft urging said shaft into engagement with said actuating shaft. Rotary actuating means may include a threaded mounting of said first named shaft on its support and means for rotating said shaft.

A dial is provided having suitable calibrations thereon and is adapted to be actuated by the lateral displacement of certain of the condenser plates referred to, so as to afford an accurate indication of the condenser capacity during operation.

Further objects and features of the invention will become apparent to those skilled in the art as the description progresses.

The invention will now be described in more detail, reference being made to the accompanying drawing, in which,

Fig. 1 shows in perspective one embodiment of my invention, in which one condenser plate is movable without rotation.

Fig. 2 is a sectional view of Fig. 1 taken on the line 3-3.

Fig. 3 is a vertical, longitudinal sectional view of another embodiment of my invention wherein a plurality of movable plates is provided.

Referring to Fig. 1, a variable condenser embodying features of the invention comprises two fixed plates 6i and 62, supported by cross-bars 63, and a plate 84 whose position between the fixed plates GI and 62, can be adjusted. Cross-bars 63 are of insulating material. The position of plate 64 with respect to the stationary plates is determined by displacement of shaft 65 on which it is mounted. Shaft passes through central openings provided for this purpose in plates SI and 52. The displacement of said shaft is only longitudinal in this modification. The actuating means comprises a threaded shaft 66 which is controlled in its backward and forward longitudinal movement by a cog wheel 61 internally threaded on to shaft 66 and provided with suitable grooves for engaging toothed wheel 68. Wheel 68 may be operated either manually or automatically. A compression spring 69 acts upon the other end of shaft 85 to maintain engagement between 65 and it. The structure avoids any rotation of th 3 movable plate 64 in the course of its displacement as a result of a pin H fixed on the shaft 68 operating within a guide slot 89 in the bearing bracket 10." This guide slots extends parallel-to the longitudinal axis of the shafts.

In its position of rest, the system is wholly symmetrical with respect to movable plate 64 which is then situated midway between the fixed plates 6i and 62. If the toothed wheel 68 is caused to turn in a direction so as to advance the shaft 68 against the action of the spring 69, the movable plate 54 will approach the fixed plate 6i, and as a result the capacity between these plates will increase. In this situation the capacity between the fixed plate 62 and the movable plate 64, will decrease, because of the increased distance therebetween. The effect of this dual capacity relationship between movable plate 64 and fixed plates 6i and 62 is such that at the beginning of the displacement of movable plate 64, the variation in capacity of the condenser as a whole will be negligible. This is for the reason that the capacity of a condenser such as is described is. at every instant. given by the following formula:

y 1 1 1 1Ka "(Ft mrym in which 2a represents the distance between the fixed plates 6i and 62, and :2 represents the displacement of the movable plate 64. K is a constant which depends on the dimensions and shape of the stationary plate structure.

Referring to Fig. 3, the condenser here shown differs from the structure of Fig. 1, in that a plurality of movable and fixed plates are employed. Further, the apparatus for controlling the adjustment of the movable plates is of a different organization and includes a dial for indicating the action of the condenser.

A support is constituted by a rear bracket 2 and a front bracket i, the latter also supporting the apparatus for controlling and indicating the condenser performance. Between brackets I and 2, and parallel to these brackets, are the fixed plates 4 of the condenser. The distance between the plates 4 is maintained constant by hollow guiding cross-bars or sleeves ii, and the spacing between the end fixed plates and the brackets is controlled by guiding cross-bars or sleeves 8 and by insulating rings 9. These sleeves and rings are threaded on shafts 49, which serve to keep both the brackets and the fixed plates in assembled condition. The shafts 49 are threaded at their ends and are fastened by nuts i3. These nuts are in turn insulated from the brackets i and 2 by means of insulating bushings l2.

On the rear bracket 2 is fixed a cup 22 which serves as a. buttress to spring 26. Plates 3 are kept in place on shaft by cross-bars or sleeves 6, emerging at one end to abut against the annular enlargement 50 of said shaft 5, and at the other end to engage nut 31 threaded on shaft 5. A pin 24 bearing against a flattened portion of shaft 5, prevents rotation of said shaft. Shaft'li, however, is free to slide longitudinally in suitable grooves. The gear case 38 is mounted on the front bracket i and is adapted to support the concondenser. Shaft 44 is held against rotation by a bolt or pin 45, which also serves to guide shaft 44 in its longitudinal displacement. Bolt 44 is in turn controlled in its movement by the interior surface of a groove 45 provided on the gear case 38 which groove extends parallel to shaft 44.

Shaft 44 is supported and given lateral displacement by member 43, which is coaxially disposed around a portion of shaft 44, within said gear case 38, and is mounted for rotation on ball bearings 5i. Member 43 is provided towards one end thereof with suitable teeth adapted to engage the teeth of cog wheel 30. Towards the other end of said member 43 there is provided a drum 4i adapted to receive the control cable, not shown.

The capacity indicating means is comprised of a graduated disc 52 supported at its center portion by a shaft 3i said shaft also supporting cog wheel 30, and adapted to be rotated thereby. Shaft 3i is centered in a support 35 carried by the front bracket i.

The portion of the condenser which is subjected to electric current is enclosed within cylindrical casing iii, to prevent deleterious action of the elements such as moisture, dust, etc., from aflecting the capacity. To avoid undesirable variations in capacity resulting from displacement of shaft 5 within said casing, the cross-bars 8 are extended beyond the fixed plates 4.

It is obvious to those skilled in the art that the invention is by no means limited to the particular organizations and structures shown. For example, the fixed and movable plates are represented as circular in the embodiments shown to facilitate turning them, but it is clear that plates of any desired forms may be used without departing from the invention. However, where the dis placement of the movable plates is secured by the rotation of said plates, it is necessary to use cir-' What is claimed is: v

1. In a variable condenser, a plurality of fixed plates mounted on a common axis and in parallel relationship, movable plates mounted on said common axis and parallel to said fixed plates, each of said movable plates being disposed be; tween two of said fixed plates, a shaft supporting the movable plates, a stationary journal bearing supporting said shaft movably along its axis, means at one end of said shaft for imparting rectilinear movement to said shaft along its axis, said last-named means comprising a second shaft linearly disposed with respect to the first-named shaft, and having a cone-shaped central end adapted to bear against the central portion of an end surface of said first-named shaft, and means for moving said second shaft in the direction of said first-named shaft.

2. A variable condenser comprising a plurality of plates coaxially mounted, certain of said plates being fixedly mounted and others of said plates being mounted for movement longitudinally of the common axis of said plates, each one of said movable plates being disposed between two of said fixed plates, said movable platesbeing mounted on a common shaft having a pin point hearing at one point thereof, arranged in said common axis and means for imparting motion to said shaft longitudinally of its axis comprising a resilient thrust bearing operative on the opposite end of said shaft to impart pressure on the shaft in .one direction and an adjustable member having a pin point engaging said bearing for effecting longitudinal movement of the plates against the influence of the resilient means.

3. A variable condenser comprising a plurality of plates coaxially mounted, certain of said plates being fixedly mounted and others of said plates being mounted for movement longitudinally of the common axis of said plates, each one of said movable plates being disposed between two of said fixed plates, said movable plates being mounted on a common shaft having a pin point bearing arranged in said common axis and means for imparting motion to said shaft longitudinally of its axis comprising a spring supported to impart pressure on the shaft in one direction and a coaxial adjusting shaft having a pin point engaging said bearing for effecting longitudinal movement of the plates against the influence of the resilient means, rotary means arranged longitudinally stationary and threaded to the adjusting shaft to effect longitudinal movement thereof. 4. A condenser according to claim 2, wherein REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS 15 Number Name Date 1,527,578 Sheriff Feb. 24, 1925 1,560,761 Cohen Nov. 10, 1925 FOREIGN PATENTS 20) Number Country Date 378,698 Great Britain Aug. 18, 1932 

